SUMMARY

This summary highlights selected information included in this joint proxy statement/prospectus and does not contain all of the information that may be important to you. You should read this joint proxy statement/prospectus and its annexes carefully and in their entirety and the other documents to which Chesapeake and WildHorse refer before you decide how to vote with respect to the proposals to be considered and voted on at the special meeting for your company. In addition, Chesapeake and WildHorse incorporate by reference important business and financial information about Chesapeake and WildHorse into this joint proxy statement/prospectus, as further described in the sections entitled “Where You Can Find More Information” and “Information Incorporated by Reference,” each beginning on page 215. You may obtain the information incorporated by reference into this joint proxy statement/prospectus without charge by following the instructions in the sections entitled “Where You Can Find More Information” and “Information Incorporated by Reference,” each beginning on page 215. Each item in this summary includes a page reference directing you to a more complete description of that item in this joint proxy statement/prospectus.

Information About the Companies (page 61)

Chesapeake Energy Corporation

6100 North Western Avenue

Oklahoma City, Oklahoma 73118

Phone: (405) 848-8000

Chesapeake is an independent exploration and production company engaged in the acquisition, exploration and development of properties for the production of oil, natural gas and NGLs from underground reservoirs. Chesapeake owns a large and geographically diverse portfolio of onshore U.S. unconventional natural gas and liquid assets. Chesapeake has leading positions in the liquids-rich resource plays of the Eagle Ford Shale in South Texas and the Anadarko Basin in northwestern Oklahoma and the stacked pay in the Powder River Basin in Wyoming. Chesapeake’s natural gas resource plays are the Marcellus Shale in the northern Appalachian Basin in Pennsylvania and the Haynesville/Bossier Shales in northwestern Louisiana and East Texas.

WildHorse Resource Development Corporation

9805 Katy Freeway, Suite 400

Houston, Texas 77024

Phone: (713) 568-4910

WildHorse is an independent oil and natural gas company focused on the acquisition, exploitation, development and production of oil, natural gas and NGL properties primarily in the Eagle Ford Shale and Austin Chalk in East Texas. WildHorse’s assets are characterized by concentrated acreage positions with multiple producing stratigraphic horizons, or stacked pay zones, and attractive single-well rates of return. WildHorse primarily operates in Burleson, Lee and Washington Counties.

Coleburn Inc.

c/o Chesapeake Energy Corporation

6100 North Western Avenue

Oklahoma City, Oklahoma 73118

Phone: (405) 848-8000

Coleburn Inc. is a direct, wholly owned subsidiary of Chesapeake. Upon the completion of the merger, Coleburn Inc. will cease to exist. Coleburn Inc. was incorporated in Delaware on October 19, 2018 for the sole purpose of effecting the merger.

The Merger and the Merger Agreement (pages 78 and 140)

The terms and conditions of the merger are contained in the merger agreement, which is attached to this document as Annex A and is incorporated by reference herein in its entirety. Chesapeake and WildHorse encourage you to read the merger agreement carefully and in its entirety, as it is the legal document that governs the merger.

The Chesapeake board and the WildHorse board each has unanimously approved and declared advisable the merger agreement and the transactions contemplated by the merger agreement. Pursuant to the terms and subject to the conditions included in the merger agreement, Chesapeake has agreed to acquire WildHorse by means of a merger of Merger Sub with and into WildHorse (which we refer to as the “merger”), with WildHorse surviving the merger as a wholly owned subsidiary of Chesapeake. Immediately following the merger, WildHorse will be merged with and into a wholly owned limited liability company subsidiary of Chesapeake (“LLC Sub”), with the LLC Sub continuing as a wholly owned subsidiary of Chesapeake (the “LLC Sub merger” and, together with the merger, the “integrated mergers”).

Effect of the Merger on Capital Stock; Merger Consideration (page 142)

As a result of the merger, each share of WildHorse common stock, including WildHorse preferred stock, which will be converted to WildHorse common stock prior to the effective time of the merger, issued and outstanding immediately prior to the effective time of the merger (excluding any shares held in treasury by WildHorse, shares owned by Chesapeake or Merger Sub or by any wholly owned subsidiary of Chesapeake or Merger Sub (which we refer to collectively as the “excluded shares”)) will be converted automatically at the effective time of the merger into the right to receive from Chesapeake:

WildHorse stockholders’ ability to receive the mixed consideration or the share consideration will not be subject to proration.

No scrip or shares representing fractional shares of Chesapeake common stock will be issued upon the exchange of eligible shares of WildHorse common stock, and such fractional share interests will not entitle the owner of such fractional share interests to vote or to have any rights of a shareholder of Chesapeake or a holder of shares of Chesapeake common stock. Each holder of shares exchanged pursuant to the merger who would otherwise have been entitled to receive a fraction of a share of Chesapeake common stock (after taking into account and aggregating all book-entry shares delivered by such holder) will receive, in lieu of such fractional

shares of Chesapeake common stock, cash (without interest) in an amount equal to the product of (i) the aggregate net cash proceeds as determined below and (ii) a fraction, the numerator of which is such fractional part of a share of Chesapeake common stock, and the denominator of which is the number of shares of Chesapeake common stock constituting a portion of the exchange fund as represents the aggregate of all fractional entitlements of all holders of WildHorse common stock. As promptly as possible following the effective time of the merger, the exchange agent shall sell at then-prevailing prices on the NYSE such number of shares of Chesapeake common stock constituting a portion of the exchange fund as represents the aggregate of all fractional entitlements of all holders of WildHorse common stock, with the cash proceeds (net of all commissions, transfer taxes and other out-of-pocket costs and expenses of the exchange agent incurred in connection with such sales) of such sales to be used by the exchange agent to fund the foregoing payments in lieu of fractional shares (and if the proceeds of such share sales by the exchange agent are insufficient for such purpose, then Chesapeake shall promptly deliver to the exchange agent additional funds in an amount equal to the deficiency required to make all such payments in lieu of fractional shares).

Election Procedures (page 144)

To elect to receive mixed consideration or share consideration for your shares of WildHorse common stock, you must indicate in the place provided on the election form, which you will receive in a separate mailing, the number of your shares of WildHorse common stock and whether you prefer to receive mixed consideration or share consideration, sign the form, and return the form in the separate envelope provided so that it is received prior to the election deadline, which is 5:00 p.m. New York City time, on the business day that is two business days prior to the closing date. Chesapeake and WildHorse will publicly announce the anticipated election deadline at least five business days prior to the anticipated closing date. If the closing date is delayed to a subsequent date, the election deadline will be similarly delayed to a subsequent date, and Chesapeake and WildHorse will promptly announce any such delay and, when determined, the rescheduled election deadline.

You will be able to specify on the election form:

If you do not submit an election form prior to the election deadline, you will be deemed to have indicated that you are making no election, and you will get the share consideration. For additional information on the election procedures, see the section entitled “The Merger Agreement—Election Procedures” beginning on page 144.

Risk Factors (page 45)

The merger and an investment in Chesapeake common stock involve risks, some of which are related to the transactions contemplated by the merger agreement. You should carefully consider the information about these risks set forth under the section entitled “Risk Factors” beginning on page 45, together with the other information included or incorporated by reference in this joint proxy statement/prospectus, particularly the risk factors contained in Chesapeake’s and WildHorse’s Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and other filings they make with the SEC. WildHorse stockholders should carefully consider the risks set out in that section before deciding how to vote with respect to the merger proposal

to be considered and voted on at the WildHorse special meeting, and Chesapeake shareholders should carefully consider the risks set out in that section before deciding how to vote with respect to the Chesapeake proposals to be considered and voted on at the Chesapeake special meeting. For additional information, see the sections entitled “Where You Can Find More Information” and “Information Incorporated by Reference,” each beginning on page 215.

Treatment of WildHorse Restricted Stock Awards in the Merger (page 143)

Immediately prior to the effective time of the merger, each outstanding award of shares of WildHorse restricted stock granted under the WildHorse stock plan will automatically vest in full and any forfeiture restrictions applicable to such shares of WildHorse restricted stock will lapse immediately. As a result, each share of WildHorse restricted stock will be treated as and will have the same rights as an unrestricted share of WildHorse common stock, including the right to elect to receive mixed consideration or share consideration, as applicable, and the right to receive the merger consideration, less applicable taxes required to be withheld with respect to such vesting.

Recommendation of the Chesapeake Board of Directors and Chesapeake’s Reasons for the Merger (page 88)

The Chesapeake board unanimously recommends that you vote “FOR” the Chesapeake issuance proposal, “FOR” the Chesapeake board size proposal and “FOR” the Chesapeake authorized shares proposal (collectively referred to as the “Chesapeake proposals”). For the factors considered by the Chesapeake board in reaching this decision and additional information on the recommendation of the Chesapeake board, see the section entitled “The Merger—Recommendation of the Chesapeake Board of Directors and Chesapeake’s Reasons for the Merger” beginning on page 88.

Recommendations of the WildHorse Board of Directors and WildHorse’s Reasons for the Merger (page 99)

The WildHorse board unanimously determined that the merger and the other transactions contemplated by the merger agreement are fair to, and in the best interests of, WildHorse stockholders, approved and declared advisable the merger agreement and the transactions contemplated by the merger agreement, including the merger, and directed that the merger agreement be submitted to the WildHorse stockholders for adoption and recommended that the WildHorse stockholders adopt the merger agreement and approve all other actions or matters necessary or desirable to give effect to the foregoing. For more information regarding the factors considered by the WildHorse board in reaching this decision and additional information on the recommendations of the WildHorse board, see the section entitled “The Merger—Recommendations of the WildHorse Board of Directors and WildHorse’s Reasons for the Merger” beginning on page 99. The WildHorse board unanimously recommends that you vote “FOR” the merger proposal, “FOR” the non-binding, advisory compensation proposal and “FOR” the WildHorse adjournment proposal.

Opinions of Financial Advisors

Opinion of Goldman Sachs & Co. LLC, Chesapeake’s Financial Advisor

On October 29, 2018, Chesapeake’s financial advisor, Goldman Sachs & Co. LLC (which we refer to as “Goldman Sachs”), delivered its oral opinion, subsequently confirmed in writing, to the Chesapeake board that, as of such date and based upon and subject to the factors and assumptions set forth therein, the share consideration and the mixed consideration, taken in the aggregate, to be paid by Chesapeake for the outstanding shares of WildHorse common stock pursuant to the merger agreement was fair from a financial point of view to Chesapeake.

The full text of the written opinion of Goldman Sachs, dated October 29, 2018, which sets forth assumptions made, procedures followed, matters considered and limitations on the review undertaken in connection with the opinion, is attached as Annex B and is incorporated by reference into this joint proxy statement/prospectus. The summary of the opinion of Goldman Sachs in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of the opinion.

Goldman Sachs provided advisory services and its opinion for the information and assistance of the Chesapeake board in connection with its consideration of the merger. The Goldman Sachs opinion is not a recommendation as to how any holder of shares of Chesapeake common stock should vote with respect to the issuance of Chesapeake common stock in the merger or any other matter.

For additional information, see the section entitled “The Merger—Opinion of Goldman Sachs & Co. LLC, Chesapeake’s Financial Advisor” beginning on page 92 and Annex B.

Opinion of Tudor Pickering Holt & Co Advisors LP, WildHorse’s Financial Advisor

WildHorse retained Tudor Pickering Holt & Co Advisors LP (which we refer to as “TPH”) as its financial advisor in connection with a potential sale of, or other business combination involving, WildHorse. On October 29, 2018, TPH rendered to the WildHorse board its oral opinion, which was subsequently confirmed by delivery of a written opinion dated October 29, 2018, that, based upon and subject to the limitations, qualifications and assumptions set forth in its opinion, as of the date of the opinion, the merger consideration to be paid to the holders of outstanding shares of WildHorse common stock pursuant to the merger agreement was fair, from a financial point of view, to such holders.

The full text of TPH’s written opinion, dated October 29, 2018, which describes, among other things, the assumptions made, procedures followed, factors considered and qualifications and limitations on the scope of the review undertaken, is attached as Annex C to this joint proxy statement/prospectus and is incorporated by reference in its entirety. The summary of TPH’s opinion set forth in this joint proxy statement/prospectus is qualified in its entirety by reference to the full text of the opinion. WildHorse stockholders are urged to read the TPH opinion carefully and in its entirety. TPH delivered its opinion for the information and assistance of the WildHorse board in connection with its evaluation of the merger. TPH did not express any opinion as to the prices at which the WildHorse common stock, the Chesapeake common stock or the securities of any other party will trade at any time. The TPH opinion speaks only as of the date and time it was rendered and not as of the time of the transactions contemplated by the merger agreement or any other time. The TPH opinion is not a recommendation as to how any holder of shares of WildHorse common stock or Chesapeake common stock should vote or act with respect to the merger or any other matter, including whether any holder of the WildHorse common stock should elect to receive the mixed consideration or the share consideration.

For additional information, see the section entitled “The Merger—Opinion of Tudor Pickering Holt & Co Advisors LP, WildHorse’s Financial Advisor” beginning on page 104 and Annex C.

Opinion of Morgan Stanley & Co. LLC, WildHorse’s Financial Advisor

WildHorse retained Morgan Stanley & Co. LLC (which we refer to as “Morgan Stanley”) as its financial advisor in connection with a potential sale of, or other business combination involving, WildHorse. Morgan Stanley delivered its oral opinion to the WildHorse board on October 29, 2018, which opinion was subsequently confirmed in a written opinion dated October 29, 2018, that, as of the date of such opinion, and subject to the various assumptions made, procedures followed, matters considered, and qualifications and limitations on the scope of the review undertaken by Morgan Stanley as set forth in its written opinion, the merger consideration to

be received by the holders of shares of the WildHorse common stock pursuant to the merger agreement was fair from a financial point of view to such holders of shares of WildHorse common stock.

The full text of Morgan Stanley’s written opinion, dated October 29, 2018, which sets forth the assumptions made, procedures followed, matters considered and qualifications and limitations on the scope of the review undertaken in connection with the opinion, is attached as Annex D to this joint proxy statement/prospectus and is incorporated by reference herein in its entirety. WildHorse stockholders should read Morgan Stanley’s opinion carefully and in its entirety for a discussion of the assumptions made, procedures followed, matters considered and qualifications and limitations on the scope of the review undertaken by Morgan Stanley in rendering its opinion. This summary is qualified in its entirety by reference to the full text of such opinion. Morgan Stanley’s opinion was directed to the WildHorse board, in its capacity as such, and addressed only the fairness from a financial point of view to the holders of the WildHorse common stock of the merger consideration to be received by such holders pursuant to the merger agreement as of the date of such opinion. Morgan Stanley’s opinion did not address any other aspects or implications of the merger. Morgan Stanley’s opinion did not in any manner address the prices at which the Chesapeake common stock would trade following the consummation of the merger or at which the WildHorse common stock or the Chesapeake common stock or any other securities would trade at any time. Morgan Stanley expressed no opinion or recommendation to any holder of shares of the WildHorse common stock or the Chesapeake common stock as to how such holder should vote at the WildHorse special meeting or the Chesapeake special meeting, respectively, or act in any manner in connection with the merger, including whether any holder of WildHorse common stock should elect to receive the mixed consideration or the share consideration.

For additional information, see the section entitled “The Merger—Opinion of Morgan Stanley & Co. LLC, WildHorse’s Financial Advisor” beginning on page 107 and Annex D.

Special Meeting of Chesapeake Shareholders (page 62)

Date, Time, Place and Purpose of the Chesapeake Special Meeting

The Chesapeake special meeting will be held on                 , 2019, at                 , Central Time, at 6100 North Western Avenue, Oklahoma City, Oklahoma 73118. The purpose of the Chesapeake special meeting is to consider and vote on the Chesapeake proposals. Approval of the Chesapeake issuance proposal by Chesapeake shareholders is a condition to the obligations of Chesapeake and WildHorse to complete the merger. Approval of the Chesapeake board size proposal and approval of the Chesapeake authorized shares proposal are not conditions to the obligation of either WildHorse or Chesapeake to complete the merger.

Record Date and Outstanding Shares of Chesapeake Common Stock

Only holders of record of issued and outstanding shares of Chesapeake common stock as of the close of business on                 ,                  (which we refer to as the “Chesapeake record date”), are entitled to notice of, and to vote at, the Chesapeake special meeting or any adjournment or postponement of the Chesapeake special meeting.

As of the close of business on the Chesapeake record date, there were                  shares of Chesapeake common stock issued and outstanding and entitled to vote at the Chesapeake special meeting. You may cast one vote on each Chesapeake proposal for each share of Chesapeake common stock that you held as of the close of business on the Chesapeake record date.

A complete list of Chesapeake shareholders entitled to vote at the Chesapeake special meeting will be available for inspection at Chesapeake’s principal place of business during regular business hours for a period of no less than ten days before the Chesapeake special meeting and during the Chesapeake special meeting.

Quorum; Abstentions and Broker Non-Votes

A quorum of Chesapeake shareholders is necessary for Chesapeake to hold a valid meeting. The presence at the Chesapeake special meeting, in person or by proxy, of the holders of a majority of the outstanding shares of Chesapeake common stock entitled to vote at the Chesapeake special meeting constitutes a quorum.

If you submit a properly executed proxy card, even if you do not vote for the Chesapeake proposals or vote to “abstain” in respect of the Chesapeake proposals, your shares of Chesapeake common stock will be counted for purposes of determining whether a quorum is present for the transaction of business at the Chesapeake special meeting. Chesapeake common stock held in “street name” with respect to which the beneficial owner fails to give voting instructions to the broker, bank or other nominee will be considered present and entitled to vote at the Chesapeake special meeting for the purpose of determining the presence of a quorum.

A broker non-vote will result if your broker, bank or other nominee returns a proxy but does not provide instruction as to how shares should be voted on a particular matter. Executed but unvoted proxies will be voted in accordance with the recommendation of the Chesapeake board.

Required Vote to Approve the Chesapeake Issuance Proposal

Approval of the Chesapeake issuance proposal requires the affirmative vote of a majority of votes cast by Chesapeake shareholders present in person or by proxy at the Chesapeake special meeting and entitled to vote on this proposal. Abstentions will have the same effect as a vote “AGAINST” the Chesapeake issuance proposal and, assuming a quorum is otherwise established, the failure of any Chesapeake shareholder to vote and broker non-votes will have no effect on the outcome of the vote.

The Chesapeake issuance proposal is described in the section entitled “Chesapeake Proposals” beginning on page 67.

Required Vote to Approve the Chesapeake Board Size Proposal

Approval of the Chesapeake board size proposal requires the affirmative vote of the Chesapeake shareholders of at least a majority of the issued and outstanding Chesapeake stock entitled to vote on this proposal. Abstentions, the failure of any Chesapeake shareholder to vote and broker non-votes will have the same effect as a vote “AGAINST” the Chesapeake board size proposal.

The Chesapeake board size proposal is described in the section entitled “Chesapeake Proposals” beginning on page 67.

Required Vote to Approve the Chesapeake Authorized Shares Proposal

Approval of the Chesapeake authorized shares proposal requires the affirmative vote of the Chesapeake shareholders of at least a majority of the issued and outstanding Chesapeake stock entitled to vote on this proposal. Abstentions and the failure of any record holder of shares of Chesapeake common stock to vote will have the same effect as a vote “AGAINST” the Chesapeake authorized shares proposal. Because brokers, banks, and other nominees have discretionary authority to vote on the Chesapeake authorized shares proposal, we do not expect broker non-votes in connection with the Chesapeake authorized shares proposal.

The Chesapeake authorized shares proposal is described in the section entitled “Chesapeake Proposals” beginning on page 67.

Voting by Chesapeake Directors and Executive Officers

As of the Chesapeake record date, Chesapeake directors and executive officers, and their affiliates, as a group, owned and were entitled to vote                  shares of Chesapeake common stock, or approximately     % of the total outstanding shares of Chesapeake common stock as of the Chesapeake record date.

Chesapeake currently expects that all of its directors and executive officers will vote their shares “FOR” the Chesapeake proposals.

Adjournment

If a quorum is not present or if there are insufficient votes for the approval of the Chesapeake issuance proposal, Chesapeake expects that the Chesapeake special meeting will be adjourned by the chairman of the Chesapeake special meeting to solicit additional proxies. At any subsequent reconvening of the Chesapeake special meeting, all proxies will be voted in the same manner as the manner in which such proxies would have been voted at the original convening of the Chesapeake special meeting, except for any proxies that have been validly revoked or withdrawn prior to the subsequent meeting.

Special Meeting of WildHorse Stockholders (page 70)

Date, Time, Place and Purpose of the WildHorse Special Meeting

The special meeting of WildHorse stockholders will be held on                 , 2019, at                 , Central Time at 920 Memorial City Way, Suite 1400, Houston, Texas 77024. The purpose of the special meeting of WildHorse stockholders is to consider and vote on the WildHorse proposals. Approval of the merger proposal by WildHorse stockholders is a condition to the obligations of Chesapeake and WildHorse to complete the merger. Approval of the non-binding, advisory compensation proposal and approval of the adjournment proposal are not conditions to the obligation of either WildHorse or Chesapeake to complete the merger.

Record Date and Outstanding Shares of WildHorse Common Stock and WildHorse Preferred Stock

Only record holders of shares of WildHorse common stock and WildHorse preferred stock at the close of business on                 ,                  (which we refer to as the “WildHorse record date”), are entitled to notice of, and to vote at, the WildHorse special meeting or any adjournment or postponement of the WildHorse special meeting.

At the close of business on the WildHorse record date, the only issued and outstanding voting securities of WildHorse entitled to vote at the WildHorse special meeting were                  shares of WildHorse common stock and 435,000 shares of WildHorse preferred stock.

You may cast one vote on each WildHorse proposal for each share of WildHorse common stock, including WildHorse preferred stock on an as-converted basis, that you held as of the close of business on the WildHorse record date.

A complete list of WildHorse’s stockholders entitled to vote at the WildHorse special meeting will be available for inspection at WildHorse’s principal place of business during regular business hours for a period of no less than ten days before the WildHorse special meeting and during the WildHorse special meeting.

Quorum; Abstentions and Broker Non-Votes

A quorum of WildHorse stockholders is necessary for WildHorse to hold a valid meeting. The presence at the WildHorse special meeting, in person or by proxy, of the holders of a majority of the outstanding shares of WildHorse common stock, including WildHorse preferred stock on an as-converted basis, entitled to vote at the WildHorse special meeting constitutes a quorum.

If you submit a properly executed proxy card, even if you do not vote for the WildHorse proposals or vote to “abstain” in respect of the WildHorse proposals, your shares of WildHorse common stock, including WildHorse preferred stock on an as-converted basis, will be counted for purposes of determining whether a quorum is present for the transaction of business at the WildHorse special meeting. WildHorse common stock held in “street name” with respect to which the beneficial owner fails to give voting instructions to the broker, bank or other nominee, and WildHorse common stock with respect to which the beneficial owner otherwise fails to vote, will not be considered present and entitled to vote at the WildHorse special meeting for the purpose of determining the presence of a quorum.

Under the current NYSE rules, brokers, banks or other nominees do not have discretionary authority to vote on any of the WildHorse proposals at the WildHorse special meeting. Because the only proposals for consideration at the WildHorse special meeting are non-discretionary proposals, it is not expected that there will be any broker non-votes at the WildHorse special meeting.

Executed but unvoted proxies will be voted in accordance with the recommendations of the WildHorse board.

Required Vote to Approve the WildHorse Merger Proposal

Approval of the merger proposal by the WildHorse stockholders is a condition to the merger and requires the affirmative vote of a majority of the outstanding shares of WildHorse common stock, including WildHorse preferred stock on an as-converted basis, entitled to vote on such proposal. Abstentions and the failure of any WildHorse stockholder to vote will have the same effect as a vote “AGAINST” the merger proposal.

The WildHorse merger proposal is described in the section entitled “WildHorse Proposals” beginning on page 76.

Required Vote to Approve the WildHorse Non-Binding, Advisory Compensation Proposal

Approval of the non-binding, advisory compensation proposal by the WildHorse stockholders requires the affirmative vote of a majority of the shares of WildHorse common stock, including WildHorse preferred stock on an as-converted basis, present in person or by proxy at the WildHorse special meeting and entitled to vote on such proposal. Abstentions will have the same effect as a vote “AGAINST” the non-binding, advisory compensation proposal and, assuming that a quorum is otherwise established, the failure of any WildHorse stockholder to vote will have no effect on the outcome of the vote.

The non-binding, advisory compensation proposal is described in the section entitled “WildHorse Proposals” beginning on page 76.

Required Vote to Approve the WildHorse Adjournment Proposal

Approval of the adjournment proposal by the WildHorse stockholders requires the affirmative vote of a majority of the shares of WildHorse common stock, including WildHorse preferred stock on an as-converted basis, present in person or by proxy at the WildHorse special meeting and entitled to vote on such proposal. Abstentions will have the same effect as a vote “AGAINST” the adjournment proposal and, assuming that a quorum is otherwise established, the failure of any WildHorse stockholder to vote will have no effect on the outcome of the vote.

The adjournment proposal is described in the section entitled “WildHorse Proposals” beginning on page 76.

Voting by WildHorse Directors and Executive Officers

As of the WildHorse record date, WildHorse directors and executive officers, as a group, owned and were entitled to vote                  shares of WildHorse common stock, or approximately     % of the total outstanding shares of WildHorse common stock, including WildHorse preferred stock on an as-converted basis, as of the WildHorse record date.

WildHorse currently expects that all of its directors and executive officers will vote their shares “FOR” the WildHorse proposals.

In connection with the execution of the merger agreement, Chesapeake entered into the voting agreements with Jay C. Graham, the NGP stockholders and with the Carlyle stockholder, wherein such stockholders agreed to vote all of the WildHorse shares held by them in favor of the approval and adoption of the merger agreement and the transactions contemplated by the merger agreement, including the merger, subject to certain exceptions. As of November 29, 2018, the 435,000 shares of WildHorse preferred stock held by the Carlyle stockholder are convertible into 32,402,059 shares of WildHorse common stock. As of the date of this joint proxy statement/prospectus, such stockholders hold and are entitled to vote in the aggregate approximately                % of the issued and outstanding shares of WildHorse common stock, including WildHorse preferred stock on an as-converted basis, entitled to vote at the WildHorse special meeting. Accordingly, as long as the WildHorse board does not change its recommendation with respect to such proposal (in which case the voting and support obligations of Jay C. Graham, the NGP stockholders and the Carlyle stockholder would apply only to an aggregate amount of WildHorse common stock, including WildHorse preferred stock on an as-converted basis, equal to 35% of the WildHorse common stock outstanding, including WildHorse preferred stock on an as-converted basis), approval of the WildHorse merger proposal at the WildHorse special meeting is assured.

In addition, Jay C. Graham, the NGP stockholders and the Carlyle stockholder irrevocably elected to receive the mixed consideration with respect to their WildHorse common stock, including WildHorse preferred stock on an as-converted basis, as applicable. Furthermore, the voting agreement with the Carlyle stockholder requires such stockholder to convert its shares of WildHorse preferred stock into WildHorse common stock prior to the effective time of the merger. See “The Merger Agreement—Voting and Support Agreements” beginning on page 175 for more information.

Adjournment

If a quorum is not present or if there are insufficient votes for the approval of the merger proposal, WildHorse expects that the WildHorse special meeting will be adjourned by the chairman of the WildHorse special meeting or by the approval of the adjournment proposal to solicit additional proxies. At any subsequent reconvening of the WildHorse special meeting, all proxies will be voted in the same manner as the manner in which such proxies would have been voted at the original convening of the WildHorse special meeting, except for any proxies that have been validly revoked or withdrawn prior to the subsequent meeting.

Interests of Chesapeake Directors and Executive Officers in the Merger (page 131)

In considering the recommendation of the Chesapeake board with respect to the Chesapeake proposals, Chesapeake shareholders should be aware that the directors and executive officers of Chesapeake have interests in the merger that may be different from, or in addition to, the interests of Chesapeake shareholders generally. These interests include, but are not limited to, the vesting of certain unvested account balances and enhanced benefits upon a qualifying termination of employment that occurs in connection with the merger. These interests are described in more detail in the section entitled “The Merger—Interests of Chesapeake Directors and Executive Officers in the Merger” beginning on page 131. The members of the Chesapeake board were aware of

and considered these interests, among other matters, in evaluating and negotiating the merger agreement, in approving the merger agreement and in determining to recommend that Chesapeake shareholders approve the Chesapeake proposals.

Board of Directors and Management of Chesapeake Following Completion of the Merger (page 131)

Subject to the approval by Chesapeake’s shareholders of the Chesapeake board size proposal prior to the effective time of the merger, Chesapeake shall take all necessary actions to cause the Chesapeake bylaws to be amended as of the effective time of the merger so that such bylaws shall provide that the maximum size of the Chesapeake board shall be increased from 10 members to 11 members.

Prior to the effective time of the merger, Chesapeake shall take all necessary corporate action so that upon and after the effective time of the merger, one person designated by WildHorse prior to the closing (the “first director”) is appointed to the Chesapeake board. The first director must be reasonably acceptable to Chesapeake; provided that any director of WildHorse as of October 29, 2018 shall be deemed reasonably acceptable to Chesapeake, without requiring any further approval from Chesapeake. Chesapeake, through the Chesapeake board, shall take all necessary action to nominate such director for election to the Chesapeake board in the proxy statement relating to the first annual meeting of the shareholders of Chesapeake following the closing.

If (i) the Chesapeake board size proposal has been approved by Chesapeake’s shareholders prior to the effective time of the merger or (ii) following the effective time of the merger a vacancy occurs on the Chesapeake board, then in either case, Chesapeake shall take all necessary corporate action so that upon and after the effective time of the merger (if the Chesapeake board size proposal has been approved), or as promptly as practicable following the first vacancy on the Chesapeake board (if the Chesapeake board size proposal has not been approved), the first director and a second person designated by WildHorse prior to the closing (the “second director”) are appointed to the Chesapeake board. The second director must be reasonably acceptable to Chesapeake; provided that any director of WildHorse as of October 29, 2018 shall be deemed reasonably acceptable to Chesapeake, without requiring any further approval from Chesapeake. Chesapeake, through the Chesapeake board, shall take all necessary action to nominate, subject to the approval of the Chesapeake board size proposal or the existence of a vacancy on Chesapeake’s board, the second director for election to the Chesapeake board in the proxy statement relating to the first annual meeting of the shareholders of Chesapeake following the closing.

Approval by Chesapeake’s shareholders of the Chesapeake board size proposal is not a condition to any party’s obligation to complete the merger. For more information on the conditions to the completion of the merger, please see the section entitled “The Merger Agreement—Conditions to the Completion of the Merger” beginning on page 169.

Upon completion of the merger, the current directors and executive officers of Chesapeake are expected to continue in their current positions, other than as may be publicly announced by Chesapeake in the normal course of business.

Additionally, Chesapeake will continue to be headquartered in Oklahoma City, Oklahoma.

Interests of WildHorse Directors and Executive Officers in the Merger (page 134)

In considering the recommendations of the WildHorse board with respect to the merger proposal, the non-binding, advisory compensation proposal and the adjournment proposal, WildHorse stockholders should be aware that the executive officers and directors of WildHorse have interests in the merger that may be different

from, or in addition to, the interests of WildHorse stockholders generally. These interests include, but are not limited to, the treatment in the merger of outstanding awards of WildHorse restricted stock held by WildHorse directors and executive officers, potential severance payments and benefits upon a qualifying termination of employment that occurs in connection with the merger and rights to ongoing indemnification and insurance coverage.

These interests are described in more detail in the sections entitled “The Merger—Interests of WildHorse Directors and Executive Officers in the Merger,” “The Merger—Treatment of WildHorse Restricted Stock Awards,” “The Merger—Executive Officer Severance Arrangements” and “The Merger—Quantification of Potential Payments and Benefits to WildHorse’s Named Executive Officers in Connection with the Transaction” beginning on pages 134, 134, 135 and 136, respectively.

Conditions to the Completion of the Merger (page 169)

Mutual Conditions

The respective obligations of Chesapeake, WildHorse and Merger Sub to consummate the merger are subject to the satisfaction at or prior to the effective time of the merger of the following conditions, any or all of which may be waived jointly by Chesapeake, WildHorse and Merger Sub, in whole or in part, to the extent permitted by applicable law:

Additional Conditions to the Obligations of Chesapeake

The obligations of Chesapeake and Merger Sub to consummate the merger are subject to the satisfaction at or prior to the effective time of the merger of the following conditions, any or all of which may be waived exclusively by Chesapeake, in whole or in part, to the extent permitted by applicable law:

Additional Conditions to the Obligations of WildHorse

The obligation of WildHorse to consummate the merger is subject to the satisfaction at or prior to the effective time of the merger of the following conditions, any or all of which may be waived exclusively by WildHorse, in whole or in part, to the extent permitted by applicable law:

Frustration of Closing Conditions

None of Chesapeake, WildHorse or Merger Sub may rely, either as a basis for not consummating the merger or for terminating the merger agreement, on the failure of any condition set forth above, as the case may be, to be satisfied if such failure was caused by such party’s breach in any material respect of any provision of the merger agreement.

No Solicitation (page 154)

No Solicitation by Chesapeake

Chesapeake has agreed that, from and after October 29, 2018, Chesapeake will, and will cause Chesapeake’s subsidiaries and their respective officers and directors to, and will instruct and use reasonable best efforts to cause its representatives to, immediately cease, and cause to be terminated, any discussion or negotiations ongoing with any third party with respect to a “Chesapeake competing proposal” (as defined in the section entitled “The Merger Agreement—No Solicitation; Changes of Recommendation—Definitions of Competing Proposals” beginning on page 159).

Chesapeake has also agreed that, from and after October 29, 2018, Chesapeake will not, and will cause Chesapeake’s subsidiaries and their respective officers and directors, and will instruct and use reasonable best efforts to cause its representatives not to, directly or indirectly:

From and after October 29, 2018, Chesapeake shall promptly advise WildHorse of the receipt by Chesapeake of any Chesapeake competing proposal made on or after October 29, 2018 or any request for non-public information or data relating to Chesapeake or any of its subsidiaries made by any person in connection with a Chesapeake competing proposal or any request for discussions or negotiations with Chesapeake or a representative of Chesapeake relating to a Chesapeake competing proposal (in each case within one business day thereof), and Chesapeake shall provide to WildHorse (within such one business day time frame) either (i) a copy of any such Chesapeake competing proposal made in writing provided to Chesapeake or any of its subsidiaries or (ii) a written summary of the material terms of such Chesapeake competing proposal (including the identity of the person making such Chesapeake competing proposal). Chesapeake shall keep WildHorse reasonably informed with respect to the status and material terms of any such Chesapeake competing proposal and any material changes to the status of any such discussions or negotiations, and shall promptly provide WildHorse with copies of any substantive correspondence and, with respect to substantive oral communications, a summary of such correspondence or communications, between: (x) on the one hand, Chesapeake or any of their representatives; and (y) on the other hand, the person that made or submitted such Chesapeake competing proposal or any representative of such person.

No Solicitation by WildHorse

WildHorse has agreed that, from and after October 29, 2018, WildHorse will, and will cause WildHorse’s subsidiaries and their respective officers and directors, and will instruct and use reasonable best efforts to cause its representatives to, immediately cease, and cause to be terminated, any discussion or negotiations ongoing with

any third party with respect to a “WildHorse competing proposal” (as defined in the section entitled “The Merger Agreement—No Solicitation; Changes of Recommendation—Definitions of Competing Proposals” beginning on page 159). WildHorse has agreed that by October 30, 2018, WildHorse will have delivered written notice to each third party that has received non-public information regarding WildHorse for purposes of evaluating any transaction that could be a WildHorse competing proposal within the six months prior to October 29, 2018 requesting the return or destruction of all confidential information concerning WildHorse, and must terminate any data access related to any potential WildHorse competing proposal previously granted to such third parties.

WildHorse has also agreed that, from and after October 29, 2018, WildHorse will not, and will cause WildHorse’s subsidiaries and their respective officers and directors, and will instruct and use reasonable best efforts to cause its representatives not to, directly or indirectly:

From and after October 29, 2018, WildHorse shall promptly advise Chesapeake of the receipt by WildHorse of any WildHorse competing proposal made on or after October 29, 2018 or any request for non-public information or data relating to WildHorse or any of its subsidiaries made by any person in connection with a WildHorse competing proposal or any request for discussions or negotiations with WildHorse or a representative of WildHorse relating to a WildHorse competing proposal (in each case within one business day thereof), and WildHorse shall provide to Chesapeake (within such one business day time frame) either (i) a copy of any such WildHorse competing proposal made in writing provided to WildHorse or any of its subsidiaries or (ii) a written summary of the material terms of such WildHorse competing proposal (including the identity of the person making such WildHorse competing proposal). WildHorse shall keep Chesapeake reasonably informed with respect to the status and material terms of any such WildHorse competing proposal and any material changes to the status of any such discussions or negotiations, and shall promptly provide Chesapeake with copies of any substantive correspondence and, with respect to substantive oral communications, a summary of such correspondence or communications, between: (x) on the one hand, WildHorse or any of their representatives; and (y) on the other hand, the person that made or submitted such WildHorse competing proposal or any representative of such person.

Prior to the time the merger proposal has been approved by WildHorse stockholders, WildHorse and its representatives may engage in the activities described in the first, second and third bullets in the second paragraph directly above with any person who has made a written bona fide WildHorse competing proposal that did not result from a breach of the obligations described in “The Merger Agreement—No Solicitation; Changes of Recommendation—No Solicitation by WildHorse” beginning on page 154; provided, however, that:

Prior to the time the merger proposal has been approved by WildHorse stockholders, WildHorse and its representatives may seek clarification from (but not engage in any negotiations with or provide any non-public information to) any person that has made a WildHorse competing proposal solely to clarify and understand the terms and conditions of such proposal to provide adequate information for the WildHorse board to make an informed determination under the paragraph above.

Changes of Recommendation (page 154)

Chesapeake Restrictions on Changes of Recommendation

Subject to certain exceptions described below, the Chesapeake board may not effect a Chesapeake recommendation change (as defined in the section entitled “The Merger Agreement—No Solicitation; Changes of Recommendation—Chesapeake: Restrictions on Changes of Recommendation” beginning on page 156).

WildHorse Restrictions on Changes of Recommendation

Subject to certain exceptions described below, the WildHorse board may not effect a WildHorse recommendation change (as defined in the section entitled “The Merger Agreement—No Solicitation; Changes of Recommendation—WildHorse: Restrictions on Changes of Recommendation” beginning on page 156).

Chesapeake: Permitted Changes of Recommendation in Connection with Intervening Events

Prior to the time the Chesapeake issuance proposal has been approved by Chesapeake shareholders, in response to a Chesapeake intervening event (as defined in the section entitled “The Merger Agreement—No Solicitation; Changes of Recommendation—Chesapeake: Permitted Changes of Recommendation in Connection with Intervening Events” beginning on page 157) that occurs or arises after October 29, 2018, Chesapeake may, if the Chesapeake board so chooses, effect a Chesapeake recommendation change if prior to taking such action:

WildHorse: Permitted Changes of Recommendation and Permitted Termination to Enter into a Superior Proposal

Prior to the time the merger proposal has been approved by WildHorse stockholders, in response to a WildHorse competing proposal that did not result from a breach of the obligations described above and in the section entitled “The Merger Agreement—No Solicitation; Changes of Recommendation—No Solicitation by WildHorse,” if the WildHorse board so chooses, cause WildHorse to effect a WildHorse recommendation change or terminate the merger agreement if:

WildHorse: Permitted Changes of Recommendation in Connection with Intervening Events

Prior to the time the merger proposal has been approved by WildHorse stockholders, in response to a WildHorse intervening event (as defined in the section entitled “The Merger Agreement—No Solicitation; Changes of Recommendation—WildHorse: Permitted Changes of Recommendation in Connection with Intervening Events” beginning on page 158) that occurs or arises after October 29, 2018, WildHorse may, if the WildHorse board so chooses, effect a WildHorse recommendation change if prior to taking such action:

Termination (page 171)

Chesapeake and WildHorse may terminate the merger agreement and abandon the merger at any time prior to the effective time of the merger by mutual written consent of Chesapeake and WildHorse.

The merger agreement may also be terminated by either Chesapeake or WildHorse at any time prior to the effective time of the merger in any of the following situations:

In addition, the merger agreement may be terminated by Chesapeake:

Further, the merger agreement may be terminated by WildHorse:

Expenses and Termination Fees (page 171)

Termination Fees Payable by Chesapeake

The merger agreement requires Chesapeake to pay WildHorse a termination fee of $120 million (which we refer to as the “reverse termination fee”) if:

In no event will Chesapeake be required to pay the reverse termination fee on more than one occasion.

Termination Fees Payable by WildHorse

The merger agreement requires WildHorse to pay Chesapeake a termination fee of $85 million (which we refer to as the “termination fee”) if:

In no event will WildHorse be required to pay the termination fee on more than one occasion.

Chesapeake Expenses Payable by WildHorse

The merger agreement requires WildHorse to pay Chesapeake an expense reimbursement of $25 million (which we refer to as the “Chesapeake expense reimbursement”) if either WildHorse or Chesapeake terminates the merger agreement due to a WildHorse stockholder approval termination event. In no event will Chesapeake be entitled to receive more than one payment of the Chesapeake expense reimbursement. If Chesapeake receives the termination fee, then Chesapeake will not be entitled to also receive the Chesapeake expense reimbursement.

WildHorse Expenses Payable by Chesapeake

The merger agreement requires Chesapeake to pay WildHorse an expense reimbursement of $35 million (which we refer to as the “WildHorse expense reimbursement”) if either WildHorse or Chesapeake terminates the merger agreement due to a Chesapeake shareholder approval termination event. In no event will WildHorse be entitled to receive more than one payment of the WildHorse expense reimbursement. If WildHorse receives the reverse termination fee, then WildHorse will not be entitled to also receive the WildHorse expense reimbursement.

No Dissenters’ or Appraisal Rights (page 139)

No dissenters’ or appraisal rights will be available with respect to the transactions contemplated by the merger agreement.

Material U.S. Federal Income Tax Consequences of the Integrated Mergers (page 177)

Chesapeake and WildHorse intend for the integrated mergers, taken together, to qualify as a “reorganization” within the meaning of Section 368(a) of the Code. It is a condition to Chesapeake’s obligation to complete the integrated mergers that Chesapeake receive a written opinion from Chesapeake tax counsel, to the effect that, on the basis of facts, representations and assumptions set forth or referred to in such opinion, the integrated mergers, taken together, will qualify as a “reorganization” within the meaning of Section 368(a) of the Code, and it is a condition to WildHorse’s obligation to complete the integrated mergers that WildHorse receive a written opinion from WildHorse tax counsel, to the effect that, on the basis of facts, representations and assumptions set forth or referred to in such opinion, the integrated mergers, taken together, will qualify as a “reorganization” within the meaning of Section 368(a) of the Code.

Assuming the integrated mergers so qualify:

HOLDERS OF WILDHORSE COMMON STOCK SHOULD READ THE SECTION ENTITLED “MATERIAL U.S. FEDERAL INCOME TAX CONSEQUENCES OF THE INTEGRATED MERGERS” BEGINNING ON PAGE 177 FOR A MORE DETAILED DISCUSSION OF THE U.S. FEDERAL INCOME TAX CONSEQUENCES OF THE INTEGRATED MERGERS. TAX MATTERS ARE COMPLICATED AND THE TAX CONSEQUENCES TO A PARTICULAR HOLDER OF WILDHORSE COMMON STOCK WILL DEPEND ON THE FACTS OF SUCH HOLDER’S SITUATION. HOLDERS OF WILDHORSE COMMON STOCK SHOULD CONSULT THEIR TAX ADVISORS AS TO THE SPECIFIC TAX CONSEQUENCES OF THE INTEGRATED MERGERS IN THEIR PARTICULAR CIRCUMSTANCES.

Comparison of Rights of Shareholders of Chesapeake and Stockholders of WildHorse (page 200)

The rights of WildHorse stockholders who receive shares of Chesapeake common stock in the merger will be governed by the Restated Certificate of Incorporation of Chesapeake, as amended (which we refer to as the “Chesapeake charter”), and the Amended and Restated Bylaws of Chesapeake, as amended (which we refer to as the “Chesapeake bylaws”), which are governed by Oklahoma law, rather than by the Amended and Restated Certificate of Incorporation of WildHorse, as amended (which we refer to as the “WildHorse charter”), and the Amended and Restated Bylaws of WildHorse, as amended (which we refer to as the “WildHorse bylaws”), which are governed by Delaware law. As a result, WildHorse stockholders will have different rights once they become

Chesapeake shareholders due to the differences in the organizational documents of WildHorse and Chesapeake and the differences between Oklahoma and Delaware law. The key differences are described in the section entitled “Comparison of Rights of Shareholders of Chesapeake and Stockholders of WildHorse” beginning on page 200.

Listing of Chesapeake Common Stock; Delisting and Deregistration of WildHorse Shares (page 139)

If the merger is completed, the shares of Chesapeake common stock to be issued in the merger will be listed for trading on the NYSE, shares of WildHorse common stock will be delisted from the NYSE and deregistered under the Exchange Act, and WildHorse will no longer be required to file periodic reports with the SEC in connection with its common stock, pursuant to the Exchange Act.

Accounting Treatment of the Merger

Chesapeake prepares its financial statements in accordance with GAAP. The accounting guidance for business combinations requires the use of the acquisition method of accounting for the merger, which requires the determination of the acquirer, the purchase price, the acquisition date, the fair value of assets and liabilities of the acquiree and the measurement of goodwill. Chesapeake will be treated as the acquirer for accounting purposes. See “The Merger—Accounting Treatment of the Merger” beginning on page 139.

SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA OF CHESAPEAKE

The following table sets forth selected historical consolidated financial data for Chesapeake (1) as of and for each of the years ended December 31, 2017, 2016, 2015, 2014 and 2013 and (2) as of and for the nine months ended September 30, 2018 and 2017. The selected historical consolidated financial data as of September 30, 2018 and for the nine months ended September 30, 2018 and 2017 and as of December 31, 2017 and 2016 and for each the years ended December 31, 2017, 2016 and 2015 was derived from Chesapeake’s unaudited condensed consolidated financial statements included in Chesapeake’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2018 and Chesapeake’s audited consolidated financial statements included in Chesapeake’s Annual Report on Form 10-K for the year ended December 31, 2017, respectively, each of which is incorporated by reference herein. The selected historical consolidated financial data of Chesapeake as of September 30, 2017 and for the years ended December 31, 2014 and 2013 and as of December 31, 2015, 2014 and 2013 have been derived from Chesapeake’s unaudited condensed consolidated financial statements as of September 30, 2017 and audited consolidated financial statements for such years, which have not been incorporated by reference herein.

The information set forth below is only a summary and is not necessarily indicative of the results of future operations of Chesapeake nor does it include the effects of the merger. This summary should be read together with other information contained in Chesapeake’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 and Quarterly Report on Form 10-Q for the quarter ended September 30, 2018, including the sections “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and the consolidated financial statements and related notes therein. For additional information, see the section entitled “Where You Can Find More Information” beginning on page 215.

SELECTED HISTORICAL CONSOLIDATED FINANCIAL DATA OF WILDHORSE

The following table sets forth selected historical consolidated financial data (1) as of and for each of the years ended December 31, 2017, 2016, 2015 and 2014 and (2) as of and for the nine months ended September 30, 2018 and 2017. The selected historical consolidated financial data of WildHorse as of September 30, 2018 and for the nine months ended September 30, 2018 and 2017 and as of December 31, 2017 and 2016 and for each the years ended December 31, 2017, 2016 and 2015 was derived from WildHorse’s unaudited condensed consolidated financial statements included in WildHorse’s Quarterly Report on Form 10-Q for the quarter ended September 30, 2018 and WildHorse’s audited consolidated financial statements included in WildHorse’s Annual Report on Form 10-K for the year ended December 31, 2017, respectively, each of which is incorporated by reference herein. The selected historical consolidated financial data of WildHorse as of September 30, 2017 and for the year ended December 31, 2014 and as of December 31, 2015 and 2014 have been derived from WildHorse’s unaudited condensed consolidated financial statements as of September 30, 2017 and audited consolidated financial statements for such years, which have not been incorporated by reference herein.

The information set forth below is only a summary and is not necessarily indicative of the results of future operations of WildHorse nor does it include the effects of the merger. This summary should be read together with other information contained in WildHorse’s Annual Report on Form 10-K for the fiscal year ended December 31, 2017 and Quarterly Report on Form 10-Q for the quarter ended September 30, 2018, including the sections “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and the consolidated financial statements and related notes therein. For additional information, see the section entitled “Where You Can Find More Information” beginning on page 215.

The following table presents a reconciliation of Adjusted EBITDAX to net (loss) income, our most directly comparable financial measure calculated and presented in accordance with GAAP.